SEA - G UG VMBERS. 



63 



is sold for sou2is in Cliinese markets. Onr native com- 

 monest species is Pentacta frondosa (Fig. 71). 



D'lQ. 71. — Common Sea-cucumber, with the gills nearly expanded. 



erton. 



After Em- 



LlTEKATURB. I 



O. J. Romanes. Jelly-fish, Star-fish, and Sea-urchins, 1885. 



J. Midler. Seven Memoirs on the Lurvte and Development of 

 Echinoderms. Berlin, 1846-54. 



A. Agassiz. Embryology of the Star-fish, 1864, 



E. Metschnikoff. Studien ilber die Entvpickelungsgeschichte der 

 Echinodermen und Nemcrtinen. St. Petersburg, 1869. 



H. Ludwig. Morphologische Studien an Echinodermen. Leip- 

 zig, 1877-78. 



